An optically active α-fluorocarboxylate, which is the target of the present invention, is an important intermediate of medicines, agricultural chemicals and optical materials. As publicly known techniques related to the present invention, particularly as practical production processes, it is possible to cite the undermentioned representative four examples. These production processes are in common in that the starting raw material is an optically active α-hydroxycarboxylate having an inverse stereochemistry to the target optically active α-fluorocarboxylate and that a hydroxyl group is converted to a leaving group (stereoretention), and a bimolecular nucleophilic substitution (stereoinversion) is conducted with a fluorine anion.
1) A process (Patent Publication 1) in which an optically active α-hydroxycarboxylate is converted to a chlorosulfite by thionyl chloride, then it is converted to a fluorosulfite by hydrogen fluoride, and finally it is pyrolyzed using a tertiary amine as catalyst.
2) A process (Patent Publication 2) in which an optically active α-hydroxycarboxylate is converted to methanesulfonate by methanesulfonyl chloride in the presence of an organic base, and it is reacted with an alkali metal fluoride.
3) A process (Patent Publication 3) in which an optically active α-hydroxycarboxylate is converted to a trifluoromethanesulfonate by trifluoromethanesulfonyl fluoride in the presence of an organic base, and it is continuously reacted with a salt or complex of the organic base and hydrogen fluoride, which has been produced as a by-product in the reaction system.
4) A process (Patent Publication 4) in which an optically active α-hydroxycarboxylate is converted to a fluorosulfate by sulfuryl fluoride in the presence of an organic base, and it is continuously reacted with a salt or complex of the organic base and hydrogen fluoride, which has been produced as a by-product in the reaction system.    Patent Publication 1: International Application Publication 2006/037887 Pamphlet    Patent Publication 2: Japanese Patent Application Publication 2006-169251    Patent Publication 3: Japanese Patent Application Publication 2006-83163    Patent Publication 4: Japanese Patent Application Publication 2006-290870